When coverage.py is running your program and measuring its execution, it needs
to know what code to measure and what code not to. Measurement imposes a speed
penalty, and the collected data must be stored in memory and then on disk.
More importantly, when reviewing your coverage reports, you don’t want to be
distracted with modules that aren’t your concern.

Coverage.py has a number of ways you can focus it in on the code you care
about.

When running your code, the coveragerun command will by default measure
all code, unless it is part of the Python standard library.

You can specify source to measure with the --source command-line switch, or
the [run]source configuration value. The value is a comma- or
newline-separated list of directories or package names. If specified, only
source inside these directories or packages will be measured. Specifying the
source option also enables coverage.py to report on unexecuted files, since it
can search the source tree for files that haven’t been measured at all. Only
importable files (ones at the root of the tree, or in directories with a
__init__.py file) will be considered, and files with unusual punctuation in
their names will be skipped (they are assumed to be scratch files written by
text editors).

You can further fine-tune coverage.py’s attention with the --include and
--omit switches (or [run]include and [run]omit configuration
values). --include is a list of file name patterns. If specified, only
files matching those patterns will be measured. --omit is also a list of
file name patterns, specifying files not to measure. If both include and
omit are specified, first the set of files is reduced to only those that
match the include patterns, then any files that match the omit pattern are
removed from the set.

The include and omit file name patterns follow typical shell syntax:
* matches any number of characters and ? matches a single character.
Patterns that start with a wildcard character are used as-is, other patterns
are interpreted relative to the current directory:

[run]omit=# omit anything in a .local directory anywhere*/.local/*# omit everything in /usr/usr/*# omit this single fileutils/tirefire.py

The source, include, and omit values all work together to determine
the source that will be measured.

Once your program is measured, you can specify the source files you want
reported. Usually you want to see all the code that was measured, but if you
are measuring a large project, you may want to get reports for just certain
parts.

The report commands (report, html, annotate, and xml) all take
optional modules arguments, and --include and --omit switches. The
modules arguments specify particular modules to report on. The include
and omit values are lists of file name patterns, just as with the run
command.

Remember that the reporting commands can only report on the data that has been
collected, so the data you’re looking for may not be in the data available for
reporting.